Title

Authors

Document Type

Technical Report

Publication Date

11-1971

Publisher

U. S. Environmental Protection Agency

Abstract

This report was prepared by the Federal Water- Quality Administration, Pacific Southwest Region, now the Environmental Protection Agency (EPA), Region IX, at the request of the State of Nevada, Department of Health, Welfare, and rehabilitation. In a letter, dated December 5, 1969, this agency asked for technical assistance, as authorized by the Federal Water Pollution Control Act, in developing discharge standards appropriate for Las Vegas Bay, Lake Mead, and the Lower Colorado River. The subsequent study was performed by EPA from January through August, 1970. The establishment of Nevada State Water Quality Standards for these waters will enable responsible officials to develop solutions for water quality problems in Las Vegas Bay and Las Vegas Wash.

Water quality standards are needed in order to (1) abate present nuisance conditions in waters of Las Vegas Bay, Lake Mead, and the Lower Colorado River, and (2) to provide a basis for the evaluation of alternative waste disposal plans under consideration by local districts using Lake Mead and the Lower Colorado River for sewage disposal. For example, one recent proposal recommends the formation of a Las Vegas area-combined-metropolitan sewage collection and treatment system which would discharge into the Lower Colorado River below Hoover Dam, (Consultants' Report, Phase 1, 1969). The curtailment of Las Vegas Wash effluent discharge may provide some mitigation for present nuisance algal conditions found in the Las Vegas Bay arm of Lake Mead. However, under this plan, it is also possible that the nutrients discharged to the river could support nuisance algal growth in downstream impoundments. Standards based on ability to support algal growth, together with dilution calculations, would permit the evaluation of the effects of this plan.